With the recent trend toward large-sized and large-capacity application apparatuses, a power semiconductor device having a high breakdown voltage, a high current capacity, and high-speed switching characteristics has become necessary.
Such a power semiconductor device should have a low on-resistance or a low saturated voltage in order to lower power loss in a conduction state when a very large current flows. Furthermore, the power semiconductor device should be able to endure a backward high voltage of a PN junction which is applied to both ends of the power semiconductor device in an off state or at the moment when the switch is turned off, that is, a high breakdown voltage characteristic.
Among power semiconductor devices a metal oxide semiconductor field effect transistor (MOSFET) is most commonly used as a field effect transistor in a digital circuit and an analog circuit.
A MOSFET using silicon carbide (SiC) may reduce an on-resistance to reduce power consumption, but electron mobility of the channel may be low such that there may be high channel resistance. A silicon carbide MOSFET applied with a trench gate having an accumulation channel has been developed to mitigate this.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.